Sea level rise is a global phenomenon, but it is hitting coastal communities harder and faster than any time in the past 6,000 years. This is due mainly to human activities, such as burning fossil fuels and pumping greenhouse gases into the atmosphere.
Rising ocean levels can damage and destroy homes, roads, schools, hospitals, and other vital infrastructure. They also cause health problems, including water-borne diseases, complications from respiratory illness, and stress and anxiety for people forced to move.
Scientists use a variety of tools to measure sea level changes, from tide gauges to satellites that track tiny shifts in Earth’s gravity as water shifts from land to ocean. This helps verify predictions from computer models that simulate the impact of climate change on the planet’s surface.
The two major causes of rising sea levels are the melting of glaciers and ice sheets, and thermal expansion (as the ocean warms, it expands). Some of this warming is natural, but about 90 percent of it is due to human activity, such as emissions of heat-trapping greenhouse gases.
Local factors like land subsidence from natural processes, the withdrawal of groundwater, changes in global precipitation patterns and torrential rainfalls can affect how fast sea level rises in a particular area. Temporary ups and downs in sea level, known as wiggles, occur over hours or days and are caused by things like regular daily tides and weather. They happen on top of the starting sea level height that is caused by climate change.
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